Add leaderboards to an app version - Configure Game Center - App Store Connect - Help - Apple Developer

Leaderboards can be added to your app version once configured. For information, view Configure leaderboards.

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Enable an app version for Game Center - Configure Game Center - App Store Connect - Help - Apple Developer

Configure achievements - Configure Game Center - App Store Connect - Help - Apple Developer

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Add leaderboards to an app version - Configure Game Center - App Store Connect - Help - Apple Developer

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